Line-spacing mechanism



P 6, 1955 c. B. LETTERMAN LINE-SPACING MECHANISM Filed Dec. 29, 1953 INVENTOR. CHARLES H LETTER/WAN BY aw/M;

United States Patent 2,717,070 LINE-SPACIN G Charles B. Letterman, Hartford, C nn., assignor to Underwood Corporation, New York, N. 'Y., a corporation of Delaware pp a ion December, 1953, Serial-No.- 400,871 '4 Claims. (Cl. 197-5114) This invention relates-.10. typewriters andsimilar machines, and mor particularly toline-spacing devices therefor.

overthrow suppressing: structure.

In the drawings:

Figure l is a sectional side-elevation showing a-papersupporting carriage of a typewriter embodying themechanism of the invention-in normal position the section being taken just inside ofthe right-hand carriage .end,

Figure 2 is a plan viewshowingtthe' left-hand portion of the carriage,

Figure 3 is a sectional side elevation similarto Figure-l but the line-spacing mechanismis shown set-for and actuated to obtain a triple line-space advance,

Figure 4 is a front-sectional elevation of the mechanism seen in Figure 2,

Figure 5 is-a side-elevation illustrating the mechanism of the inventionset for andaetuated to obtaina' singletooth line space, Y

Finally, Figure 6 showsin enlargedaspect an active contact relation of a line-space pawl with -a line-space wheel. 7

Now referring generally to the drawings, a usual cylindrical paper feeding roll. or platen-10 carries at the left end thereof concentrically thereon a-line-space wheel 11 11 for swinging relation therewith.

The disk has leftwardly extending therefrom an element 21 that operates in a downreaching fork 2.2 of a member 23 which by means of pins 24 has pivotal support upon two vertically spaced outwardly reaching branches 25 of the left carriage end 13. The pins 24 aflord for 2,71 7,070 Patented Sept. 6, 1 955 lever 28 ending ina A spring'29,

finger-piece, not. shown. see particularly Figures 2 andzA-eonstantly pin 31 on the carriage end:1-3; to; thereby; determine for the diskv20 and the, leverstructure :23, ZSvtheir; normal positions.

The stated pin ;31; has ,a reducedtportionwhereagainst a bevel on the feedngi end of the. pawl: 16 normallyidies to hold the pawl :free of; the line-space wheelglh lsaid pawl under the urgeofa spriiigfiiidiiferent line-space positions. Theisaidradapted to be moved clear of the line-spacewheelbya throw-off pintle 42 and which'are radiallyr dgisposed variously distant from such axis. By appropriately setting :said member any one of the; three,- vnotches A 47& isiadapted to be brought into the operating path of said nose140. vThe bases of the several matches 47 afiord stopping abutments with the member 41-to block or suppress outward .displacement of the pawl. Specifically referring to Figures 3, and 5, it will be noted that the pawl nose.

lows also that the wheel 11 overthrow.

It is to be noted further that as the line-space lever 28 is released and the pawl 16 under the urge of the spring 29 is drawn in reverse direction, the feeding end of the pawl 16 must be free to glide reversely over the tooth immediately trailing it.

From Figures 3 side of the pawl nose 40 has only contact at B in the tapering away allows the nose 40 to disengage itself freely from the stated lever-interlock with the member 41 when the feeding end of the pawl 16 in returning and bypassing the first tooth 12 is displaced upwardly and the nose 49 consequently swings downwardly.

The upper side of each of the notches 47 need only engage the nose 40 at the point A, and may be fully clear of the nose intermediate such point and the abutment 43. The handle 43 by which the member 41 is settable has a downwardly reaching extension or arm 50 which is flexible somewhat endwise of the carriage. Said arm 50 near its lower end has facing toward the adjacent carriage end 13 a blister 51 adapted to enter any one of three indentations 52 provided on a carriage-supported detent plate 53. Said plate 53 is accommodated between the carriage side wall 13 and the handle 43, and is pivotally carried on the pintle 42 for adjustment concentrically thereabout for properly correlating the position of the notches 47 with the pawl nose 40. Said plate 53 is secured in adjusted position by a clamping screw 54 entering a slot 55 in the plate and screwed into the carriage end 13.

Having specifically described the invention in a preferred form, what is claimed is:

1. A line-spacing mechanism for a typewriter or the like, comprising in combination, an element having a succession of line-spacing teeth and being advanceable in a direction of succession of such teeth, a pivotal pawl actuatable to advance said element in said direction by driving engagement with the teeth thereof and to ratchet in a reverse direction idly over such teeth, means comprising a pivotal support for said pawl, actuatable and restorable respectively to actuate and return said pawl, a member pivotally settable to different angular positions, a pivotal support for said member, and abutment means oppositely on said pawl and said member engageable in the ditferent settings given to the latter to limit the actuation of said pawl to give different integers of tooth advances to said element, said abutment means being arranged so that in all movement limits reached by said pawl there exists an appreciable distance between the said two pivotal supports, said member and said pawl having in each of the movement limits reached by said pawl coacting contacting faces at two different locations intermediate said pivotal supports to provide final lever-interlocks therebetween which will hold the pawl positively in toothed mesh with said element to suppress overthrow of the latter, said contacting faces arranged to allow reverse movement of said pawl over said teeth at the restoration of said actuatable means.

2. A line-spacing mechanism for a typewriter or the like, comprising in combination, an element having a succession of line-spacing teeth and being advanceable in a direction of succession of such teeth, a pivotal pawl actuatable to advance said element in said direction by driving engagement with the teeth thereof and to ratchet in a reverse direction idly over such teeth, means comprising a pivotal support for said pawl, actuatable and restorable respectively to actuate and return said pawl, a member pivotally settable to different angular positions, a pivotal support for said member, and means oppositely on said pawl and said member engageable in the different angular settings given to the latter to limit the actuation of said pawl to give different integers of tooth advances to said element and additionally to engage said pawl with said member in a lever-interlock at two different locations intermediate said pivotal supports, said engageable means comprising oppositely on said pawl and said member nose means and notch means.

3. A line-spacing mechanism for a typewriter or the like, comprising in combination, an element having a succession of line-spacing teeth and being advanceable in a direction of succession of such teeth, a pivotal pawl actuatable to advance said element in said direction by driving engagement with the teeth thereof and to ratchet in a reverse direction idly over such teeth, means comprising a pivotal support for said pawl, actuatable and restorable respectively to actuate and return said pawl, a nose unitary with said pawl, a pivoted stop member engageable by said nosesto terminate the actuation of said pawl and settable to difierent angular positions, and a pivotal support forlsaid member, said member provided with a plurality of angularly spaced notches substantially radially to its-pivotal support, abutments being afforded severally bythe bases of said notches, for engagement by said nose to limit variously the actuation of said pawl in conformance with desired integers of required tooth advances of said element, said nose when engaging any of said abutments having opposite contact with said member in the entered notch at two points intermediate the said. two pivotal supports to hold the pawl in overthrow-preventing mesh with the toothed element, said notches relatively to said nose being formed to allow reverse movement of the pawl over said teeth.

4. A line-spacing mechanism for a typewriter or the like, comprising in combination, a toothed line-space wheel, a pull-type pawl actuatable to turn said wheel in advance direction by' driving engagement with its teeth and to ratchet in reverse direction over such teeth, means comprising arpivotal support for, said pawl, actuatable and restorable respectively to actuate and return said pawl, a nose reaching out from said pawl generally in the actuating direction thereof, a member pivotally settable to difierentangular positions, and a pivotal support for said member disposed generally in the direction in which said nose moves at actuation of said pawl, said member for each'possible angular setting thereof being provided with a notch for the noseto enter thereinto at the actuation of saidpawl; said notches'disposed on said member so thatfor the'difierent settings given to said member the nose is arrested when the line space wheel has received a different integer of tooth advance and said nose, at arrest by the said member in each notch, having contact in such notch at opposite sides thereof at two different locations between the two pivotal supports in a manner to lock said nose against movement toward the line-space wheel. I

References Cited in the file of this patent UNITED STATES PATENTS 832,244 Dennis Oct. 2, 1906 911,275 Smith Feb. 2, 1909 2,599,535 Avery et a1. June 10, 1952 

